Yttrium
naon Yttrium is an element that's symbol is Y''' and has the number '''39. It is a silver metallic transition metal that has properties similar to lanthanoids and is a rare earth mineral. The only stable isotope, 89Y is the only naturally occurring isotope. Johan Gadolin discovered the Yttrium inside some ytterbite in 1789, but it was named by Anders Gustaf Ekeberg. The most important use of the element is making phosphors. Other uses are production of electrodes, electrolytes, electron filters, lasers, and superconductors. Properties Yttrium is soft and silver-metallic, and is a highly chrystalline transition metal. It is less electronegative than the element scandium, more electronegative than lanthanum, but less electronegative than zirconium. The pure element is stable in air in bulk form because the protective oxide (Y2O3) film on the surface. Similarities to lanthanoids Yttrium is so similar to the lanthanoids, the element was grouped with them as a rare earth element. Chemically, the element resembles lanthanoids more than it does its neighbors. It often falls in same range of reaction order, resembling terbium and dysprosium at its chemical relativity. One of the notable differences between yttrium and lanthanoids is that yttrium is almost exclusively trivalent, while most lanthanoids have valences of other than 3. naom Compounds As a trivalent transition metal, Yttrium forms some inorganic compounds, mostly in the oxidation state of +3. A good example of this is yttrium (III) oxide (Y2O3) also known as yttria. Water reacts with yttrium and its compounds to create hydrogen gas and Y2O3. Concentrated nitric and hydrofluoric acids do not rapidly destroy yttrium, but other stronger acids do. With halogens, yttrium forms yttrium(III) fluoride (YF3), yttrium(III) chloride (YCl3), and yttrium(III) bromide (YBr3) all of which at temperatures above roughly 200 degrees celcius. Carbon, phosphorus, selenium, silicon and sulfur all form compounds with yttrium at elevated temperatures. Nucleosynthesis ]] Yttrium in the solar system was formed through stellar nucleosynthesis, mostly by the s-process, but also by the r-process. The r-process consists of rapid neutron capture of lighter elements during supernova explosion. The s-process is a slow neutron capture of lighter elements inside red giant stars. The most abundant source of Yttrium in the solar system comes from the star Mira. Isotopes ]] For more information, see Yttrium isotopes Yttrium isotopes are close to the most common products of the nuclear fission of uranium occurring in nuclear explosions and nuclear reactors. With waste management, the most important yttrium isotopes are 91Y and 90Y, with half-lives of 58.51 days and 64 hours. All Group 3 elements have an odd number of protons making each of these elements have few stable isotopes. Yttrium alone has only one stable isotope, 89Y, which is also its only naturally occurring one. At least 32 synthetic isotopes of yttrium have been created, ranging in mass number from 76 to 108. The least stable isotope of yttrium is 106Y with a half-life of >150 ns and the most stable isotope is 88Y with a half-life of 106.626 days. Besides the isotopes 91Y, 87Y, and 90Y, with half lives of 58.51 days, 79.8 hours, and 64 hours, respectively, all other isotopes have half lives of less than a day and most of those have half-lives of less than an hour. History In 1787, Carl Axel Arrhenius discovered a heavy black rock near the village named Ytterby. Thinking this was an unknown mineral containing tungsten, he named the mineral ytterbite and sent samples to some chemists for testing. , the discoverer of yttrium]] Johan Gadolin found a new oxide in the sample Arrhenius gave him in 1789. In 1794, he published and completed his analasys. Anders Gustaf Ekeberg confirmed this in 1797, and named the oxide yttria. In 1843, Carl Gustav Mosander found that yttria contained three oxides, yttrium oxide, terbium oxide, and erbium oxide. After these were identified, Jean Charles Galissard de Marignac discovered a new oxide, ytterbium oxide in 1878. Abundance Yttrium is found in many rare earth minerals, and some in uranium ore, but it is never found in nature as a free element. Production The similarity between Yttrium and the lanthanoids, leaving it enriched by the same process and same ores as lanthanoids. A small seperation between light rare earth elements (LREE) and heavy rare earth elements (HREE), but the seperation is never complete. There are 4 sources for REEs. *Carbonate and fluoride with ore such as bastnäsite contains an average of 0.1% of yttrium compared to the 99.9% in 16 other REEs. *Monazite, which is mostly a phosphate is a placer deposit of sand and is created through eroded granite. Monazite contains 2 or possibly 3% of yttrium. The largest deposits were found in India and Brazil, making these countries the countries with the most yttrium. *Xenotime, an REE phosphate contains up to 60% of yttrium or yttrium phosphate (YPO4). The largest mine for xenotime is in the Bayan Obo deposit in China. *Ion absorption clays are the weathering granite, and the final ore concentrate can contain up to 8% of yttrium. The element can also be found in samarskite and fergusonite. Uses superconductor]] Yttrium oxide sulfide phosphors give red color in color television, though the red color itself is created by the europium, while the yttrium from the electron gun and places it in the phosphor. Compounds of yttrium are used as a catalyst for ethylene polymerization. Yttrium is also used in YBCO superconductors. Precautions Water soluble compounds are considered mildly toxic, while the insoluble compounds are not toxic. In experiments with animals, it shows that it may cause lung and liver damage. Exposure to yttrium in humans can cause lung disease. Workers exposed to yttrium europium vanadate dust experience mild eye, skin and respiratory tract irritation. Gallery 39.gif|The electron shell of yttrium. Yttrium 1.jpg|A chunk of yttrium-89, the only stable isotope of yttrium. References *Yttrium on Wikipedia Category:Yttrium Category:Transition metals Category:Rare earth elements Category:Group 3 Category:Period 5